Used 12mm textured coated board (Siebdruckplatte), put on adhesive bitumen felt (Dachpappe). I could reuse the old spines but the previous boards were rotted all to hell. Painted all the cuts and wood surfaces with this Induline SW-910 stuff for protection against water. Makes a nice, smooth and tough surface once it's dry. The fascia boards are beech L-profiles cut to length and at a 12 degree angle on one side. Made a model in CAD and printed an overlay out of paper. I didn't order enough of the beech do get all eight fascia boards done, I am short by about 40mm, damn. Screws are all stainless.